1. Field of the Invention
The present invention relates to an arrangement for making secure from sliding a spigot-and-socket joint for the connection of a pipe end with the socket end of a connecting pipe, which joint utilizes a securing ring axially held on the socket end and with a seal in the base of the socket.
2. The Prior Art
Non-sliding arrangements for spigot-and-socket joints are known in various forms of construction. As regards these, two groups may essentially be distinguished. In a first group of non-sliding arrangements the spigot-and-socket joint is held together by means of a clamp divided into two parts along the direction of the tube axis, this clamp surrounding the spigot-and-socket joint on the external side and being supported on the external periphery of the so-called spigot end of the one pipe and on the external periphery of the socket of the other pipe.
In the second group of spigot-and-socket joints a securing ring is used, this ring, and/or the sealing parts lying at the base of the socket, being so constructed that they can absorb pushing forces acting on the spigot-and-socket joint.
The main task of a non-sliding arrangement without doubt consists of ensuring as reliable as possible an absorption of pushing forces, but the properties afforded by spigot-and-socket joints, i.e. the deflectability and the electric connection of the pipe ends, should at the same time be preserved. In addition, a simple and easy laying of the pipes should be afforded.
The known non-sliding arrangements of both the first and second groups are not in a position to fulfil all the requirements mentioned above. With the non-sliding arrangements of the first group, the deflectability of the tubes is not ensured in the case of the majority of forms of construction. Additionally, since the pipe clamps used are relatively thick-walled, they can be fitted to the external diameter only with difficulty, as they must have an internal diameter which corresponds at least to the largest possible pipe diameter. For this reason provision is made externally for abutments which, e.g., are constructed at the so-called spigot end as a weld bead, at the socket end as an external collar.
With the non-sliding arrangements of the second group, the securing ring may be used to absorb the pushing forces when it is held in axial direction at the socket end. This is the case in particular with the securing ring constructed nowadays mostly as a screw-on ring. The screw-on ring has an external coarse thread which can be screwed in a counterthread arranged on the internal side of the socket. If the securing ring is designed as a press-on ring, it is held in axial direction by means of screws disposed in the socket end. With the securing ring thus constructed, pushing forces can indeed be absorbed, but considerable difficulties are caused when endeavoring to connect those parts which are used for the non-sliding arrangement with the pipe having the so-called spigot end in such a way that this pipe is held non-slidably in the socket. In a known method of construction a clamping ring, which has been slit and is then disposed in the base of the socket is used, which is supported by means of a slanting or arched surface on a slanting surface of the screw-on ring. By means of the slanting surface, a radial force is to be exerted on the clamp ring which thereby is pressed with its internal periphery which has a roughening or grooving onto the external periphery of the pipe with the spigot end. Although the clamp ring is constructed to be flexible by means of additional recesses extending along the direction of the pipe axis, a clamping of the pipe secure from sliding is not achieved, because on the one hand the clamping surface of the clamp ring restricted in its constructional height cannot be kept sufficiently great, and on the other hand the radial force exerted by the screw-on ring is considerably reduced by friction. The other conditions which are to be laid upon a good spigot-and-socket joint are fulfilled by this known construction, i.e., retaining the normal socket pipe dimensions and deflectability of the pipes. However, the non-sliding arrangement itself, as already mentioned, is not completely reliable.
Accordingly, the object of the invention is to construct a non-sliding arrangement of the type first defined above in such a manner that the retaining of the normal socket dimensions, the deflectability of the pipes and also the electric connection between the pipes are ensured, while in addition a satisfactory non-sliding arrangement is achieved.